This invention pertains to the art of heating rails during railroad track installation. The invention is particularly applicable for use in heating continuous rails in conjunction with railroad track installation. However, it will be appreciated that the invention has broader applications and may be advantageously adopted and used in other environments.
Many recent advancements have been made in the laying of railroad track. A popular method in use today employs continuous welded rail. In this operation, individual sections of rail, each being approximately a quarter mile long, are laid on a prepared rail bed by a rail laying device. The rail laying device moves at a constant speed dispensing and initially aligning the quarter mile long rails. At appropriate junctures, i.e. the end of one quarter mile section and the beginning of another quarter mile section, a weld is made to join the two sections. Following the rail laying device at an appropriate distance and pace is an anchoring device for anchoring the rail to the prepared bed at appropriate locations. Generally speaking, this same process applies to replacement of worn rails in existing rail lines.
As a result of investigations of this rail laying technique, it has been found that anchored rails deform, due primarily to climatic changes, causing kinks and pull-aparts in the anchored rail. Pull-aparts cause one end of a rail to pull away from an adjoining end, thus creating a gap between the rails. A kink in one of the rails typically results in a distortion of the rail and non-parallel arrangement of the rails. Kinks and pull-aparts are, of course, a cause for concern as either presents the potential for derailing and/or rough ride of a railcar thereover. Therefore, it is desirable to anchor the rails in such a manner as to preclude the rails from kinking or pulling apart.
It has been determined that it is possible to control elongation of a rail be preheating the rail to a nominal temperature as it is being anchored. By controlling the elongation of the rail during the anchoring procedure and thus laying the rail under controlled, predetermined conditions, it is possible to limit the development of kinks and pull-aparts. Therefore, preheating a rail is deemed desirable for both increasing the durability of the welds between the rail sections and to control the elongation of the rail during the anchoring procedure.
Prior attempts to preheat the rails during installation have been attempted using propane heating systems. Drawbacks in the propane heating system include an inconsistency in the heating of the rail, since some sections of the rail may be heated to a higher temperature than other sections. This inconsistent heating occurs since some burners used in the system produce a higher temperature than other burners.
An additional problem with a propane based heating system is the tendency of the burners to burn and scorch the wooden ties to which the rails are anchored. Ignition of brush located alongside the railroad right-of-way is also a problem associated with the use of propane burners. There is a further concern as to the safety of the operators working with an open flame environment and working in close proximity to large amounts of propane gas.
As installation of rail is an ongoing process, including replacement of worn rails in existing systems and the laying of rails for new rail lines, there is a need to develop a more efficient and controlled manner of heating the rails during installation. It has, therefore, been considered desirable to develop a self-propelled rail heating device. Such a device should be economical to manufacture, have means to accurately and evenly heat the rails in a controlled manner, be of a sturdy, safe, overall construction, and be arranged to perform its operations in concert with the additional devices in a continuous rail laying operation. The subject invention is deemed to meet the foregoing needs and others.